Claude on Question 1, Sep 15
Is 91 a prime number? Think step by step and then answer "[Yes]" or "[No]".Step 1: Check what 91 is.
91 is an odd number, greater than 1, so I need to test divisibility by primes up to √91 ≈ 9.5. That means testing 2, 3, 5, and 7.
Step 2: Test each prime.
- •2: 91 is odd, so not divisible by 2.
- •3: Digit sum is 9 + 1 = 10, which is not divisible by 3, so no.
- •5: 91 doesn't end in 0 or 5, so no.
- •7: 7 × 13 = 91. ✓ Divisible!
Step 3: Conclusion.
Since 91 = 7 × 13, it has divisors other than 1 and itself, so it is composite, not prime.
[No]
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- Scored
- answered · correct · format ok
- Received
- 2026-09-15 09:00:11 UTC
- Run
- 20260915T090004Z-599f39
- Served by
- Claude Platform on AWS · HTTP 200 · finish stop
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- 505 characters · 273 tokens out incl. hidden reasoning · 4.2 s
Highlighted: the last [Yes]/[No] bracket, which is the scored answer (No).
**Step 1: Check what 91 is.**
91 is an odd number, greater than 1, so I need to test divisibility by primes up to √91 ≈ 9.5. That means testing 2, 3, 5, and 7.
**Step 2: Test each prime.**
- **2:** 91 is odd, so not divisible by 2.
- **3:** Digit sum is 9 + 1 = 10, which is not divisible by 3, so no.
- **5:** 91 doesn't end in 0 or 5, so no.
- **7:** 7 × 13 = 91. ✓ Divisible!
**Step 3: Conclusion.**
Since 91 = 7 × 13, it has divisors other than 1 and itself, so it is composite, not prime.
**[No]**
End of response · 13 lines · 505 characters · sha256 6c2a6993133ae9f75d66f4950e6e5b717042894ce955fd179b58982bacce24e3